/*
 * Copyright 2007-2013 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springbyexample.mvc.method.annotation;

import java.io.IOException;
import java.lang.annotation.Annotation;
import java.lang.annotation.Inherited;
import java.util.ArrayList;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springbyexample.mvc.bind.annotation.RestResource;
import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.core.type.filter.AbstractTypeHierarchyTraversingFilter;
import org.springframework.core.type.filter.TypeFilter;
import org.springframework.data.repository.Repository;
import org.springframework.data.repository.RepositoryDefinition;
import org.springframework.util.Assert;


/**
 * Scans for REST service interfaces to register as controller endpoints.
 * 
 * @author David Winterfeldt
 */
public class RestServiceComponentProvider extends ClassPathScanningCandidateComponentProvider {

    final Logger logger = LoggerFactory.getLogger(getClass());
    
    /**
     * Creates a new {@link RepositoryComponentProvider} using the given {@link TypeFilter} to include components to be
     * picked up.
     * 
     * @param includeFilters the {@link TypeFilter}s to select repository interfaces to consider, must not be
     *          {@literal null}.
     */
    public RestServiceComponentProvider() { //Iterable<? extends TypeFilter> includeFilters) {
        super(false);

//        Assert.notNull(includeFilters);
//
//        if (includeFilters.iterator().hasNext()) {
//            for (TypeFilter filter : includeFilters) {
//                addIncludeFilter(filter);
//            }
//        } else {
            super.addIncludeFilter(new AnnotationTypeFilter(RestResource.class, true, true));
//            super.addIncludeFilter(new InterfaceTypeFilter(PersistenceMarshallingService.class));
//            super.addIncludeFilter(new AnnotationTypeFilter(RepositoryDefinition.class, true, true));
//        }

//        addExcludeFilter(new AnnotationTypeFilter(NoRepositoryBean.class));
    }

    /**
     * Custom extension of {@link #addIncludeFilter(TypeFilter)} to extend the added {@link TypeFilter}. For the
     * {@link TypeFilter} handed we'll have two filters registered: one additionally enforcing the
     * {@link RepositoryDefinition} annotation, the other one forcing the extension of {@link Repository}.
     * 
     * @see ClassPathScanningCandidateComponentProvider#addIncludeFilter(TypeFilter)
     */
    @Override
    public void addIncludeFilter(TypeFilter includeFilter) {
        List<TypeFilter> filterPlusInterface = new ArrayList<TypeFilter>(2);
        filterPlusInterface.add(includeFilter);
//        filterPlusInterface.add(new InterfaceTypeFilter(PersistenceMarshallingService.class));

        super.addIncludeFilter(new AllTypeFilter(filterPlusInterface));

        List<TypeFilter> filterPlusAnnotation = new ArrayList<TypeFilter>(2);
        filterPlusAnnotation.add(includeFilter);
//        filterPlusAnnotation.add(new AnnotationTypeFilter(RepositoryDefinition.class, true, true));

        super.addIncludeFilter(new AllTypeFilter(filterPlusAnnotation));
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider#isCandidateComponent(org.springframework.beans.factory.annotation.AnnotatedBeanDefinition)
     */
    @Override
    protected boolean isCandidateComponent(AnnotatedBeanDefinition beanDefinition) {
        boolean isNonRepositoryInterface = RestServiceUtils.isRestServiceInterface(beanDefinition.getBeanClassName());
        boolean isTopLevelType = !beanDefinition.getMetadata().hasEnclosingClass();

        return isNonRepositoryInterface && isTopLevelType;
    }

//    /**
//     * {@link org.springframework.core.type.filter.TypeFilter} that only matches interfaces. Thus setting this up makes
//     * only sense providing an interface type as {@code targetType}.
//     * 
//     * @author Oliver Gierke
//     */
//    private static class InterfaceTypeFilter extends AssignableTypeFilter {
//
//        /**
//         * Creates a new {@link InterfaceTypeFilter}.
//         * 
//         * @param targetType
//         */
//        public InterfaceTypeFilter(Class<?> targetType) {
//            super(targetType);
//        }
//
//        /*
//         * (non-Javadoc)
//         * @see org.springframework.core.type.filter.AbstractTypeHierarchyTraversingFilter#match(org.springframework.core.type.classreading.MetadataReader, org.springframework.core.type.classreading.MetadataReaderFactory)
//         */
//        @Override
//        public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException {
//            return metadataReader.getClassMetadata().isInterface() && super.match(metadataReader, metadataReaderFactory);
//        }
//    }

    // Copy of Spring's AnnotationTypeFilter until SPR-8336 gets resolved.

    /**
     * A simple filter which matches classes with a given annotation, checking inherited annotations as well.
     * <p>
     * The matching logic mirrors that of <code>Class.isAnnotationPresent()</code>.
     * 
     * @author Mark Fisher
     * @author Ramnivas Laddad
     * @author Juergen Hoeller
     * @since 2.5
     */
    private class AnnotationTypeFilter extends AbstractTypeHierarchyTraversingFilter {

        private final Class<? extends Annotation> annotationType;

        private final boolean considerMetaAnnotations;

        /**
         * Create a new AnnotationTypeFilter for the given annotation type. This filter will also match meta-annotations. To
         * disable the meta-annotation matching, use the constructor that accepts a ' <code>considerMetaAnnotations</code>'
         * argument. The filter will not match interfaces.
         * 
         * @param annotationType the annotation type to match
         */
//        public AnnotationTypeFilter(Class<? extends Annotation> annotationType) {
//            this(annotationType, true);
//        }

        /**
         * Create a new AnnotationTypeFilter for the given annotation type. The filter will not match interfaces.
         * 
         * @param annotationType the annotation type to match
         * @param considerMetaAnnotations whether to also match on meta-annotations
         */
//        public AnnotationTypeFilter(Class<? extends Annotation> annotationType, boolean considerMetaAnnotations) {
//            this(annotationType, considerMetaAnnotations, false);
//        }

        /**
         * Create a new {@link AnnotationTypeFilter} for the given annotation type.
         * 
         * @param annotationType the annotation type to match
         * @param considerMetaAnnotations whether to also match on meta-annotations
         * @param considerInterfaces whether to also match interfaces
         */
        public AnnotationTypeFilter(Class<? extends Annotation> annotationType, boolean considerMetaAnnotations,
                boolean considerInterfaces) {
            super(annotationType.isAnnotationPresent(Inherited.class), considerInterfaces);
            this.annotationType = annotationType;
            this.considerMetaAnnotations = considerMetaAnnotations;
        }

        @Override
        protected boolean matchSelf(MetadataReader metadataReader) {
            AnnotationMetadata metadata = metadataReader.getAnnotationMetadata();
            return metadata.hasAnnotation(this.annotationType.getName())
                    || (this.considerMetaAnnotations && metadata.hasMetaAnnotation(this.annotationType.getName()));
        }

        @Override
        protected Boolean matchSuperClass(String superClassName) {
            if (Object.class.getName().equals(superClassName)) {
                return Boolean.FALSE;
            } else if (superClassName.startsWith("java.")) {
                try {
                    Class<?> clazz = getClass().getClassLoader().loadClass(superClassName);
                    return (clazz.getAnnotation(this.annotationType) != null);
                } catch (ClassNotFoundException ex) {
                    // Class not found - can't determine a match that way.
                }
            }
            return null;
        }
    }

    /**
     * Helper class to create a {@link TypeFilter} that matches if all the delegates match.
     * 
     * @author Oliver Gierke
     */
    private class AllTypeFilter implements TypeFilter {

        private final List<TypeFilter> delegates;

        /**
         * Creates a new {@link AllTypeFilter} to match if all the given delegates match.
         * 
         * @param delegates must not be {@literal null}.
         */
        public AllTypeFilter(List<TypeFilter> delegates) {

            Assert.notNull(delegates);
            this.delegates = delegates;
        }

        /* 
         * (non-Javadoc)
         * @see org.springframework.core.type.filter.TypeFilter#match(org.springframework.core.type.classreading.MetadataReader, org.springframework.core.type.classreading.MetadataReaderFactory)
         */
        public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException {

            for (TypeFilter filter : delegates) {
                if (!filter.match(metadataReader, metadataReaderFactory)) {
                    return false;
                }
            }

            return true;
        }
    }

}

